And so to Reading and Leeds, the no-frills Big Gig in a Field that acts as the solo-squealing encore for the UK festival season. It sneers at Bestival's firework finale as it casually sets fire to its toilet blocks. It snorts at the piss bottles thrown at Cher Lloyd at V as it lobs whole deckchairs at 50 Cent. Here there are no Patagonian poetry grottos, no naked swimming, fancy dress pirate parades, English National Ballet, wishing trees, or Alice in Wonderland hookah lounges. At Reading you have two choices: rock, or get off the pot.

This year sees a relaxing of the metal apartheid that has traditionally seen one day of the festival given over to the longhairs throttling "axes" as if Mordor has moved to Berkshire. Rock acts are now integrated throughout the weekend, and only the Friday afternoon on the – now ridiculously red – main stage is uniformly hirsute and heavy, and surprisingly homegrown. Openers Deaf Havana bleed American with their accomplished impression of Gaslight Anthem blue-collar bluster, but as soon as they open their mouths to apologise for a "backdrop the size of a postage stamp", it's clear they are from Norfolk.

The more riffophobic of the teenage hordes roaming Reading on Friday afternoon, though, might still struggle for refuge. Hitting the Festival Republic stage to find out if O Brother are a third incarnation of the much-maligned grit-pop gobshites, we find a pleasant collegiate type announcing that his band are from Georgia, like that nice REM. Then they start thrashing their barnets like Fifty Shades of Grey buttock beaters and making a sound like a kraken belching. But then, as Reading and Leeds annually proves, one man's atonal cacophony is another's siren call; over in the NME/Radio One tent, Welsh punks Future of the Left tear through yelping hardcore classics such as Lightsabre Cocksucking Blues and To Hell with Good Intentions (from their former incarnation as McLusky, and including the deathless lyric "we take more drugs than a touring funk band") to the delight of this blissed-out blogger.

Then … pandemonium. A stampede of teenagers descend like wildebeest on the tent, the most up-for-it Friday morning crowd in festival memory, rapturously cheering every roadie tapping a microphone, every strobe test, every time someone shouts "Fenton!". It turns out Hadouken! are massive – who knew? The modernist arcade-rock of Mecha Love, full of noises like a broken Dance Dance Revolution machine, has the teenage crowd in rave raptures and the once corny That Boy That Girl ("that boy's a Hoxton hero … that girl's an indie Cindy") is received like a new Seven Nation Army. It must be something they put in the luminous face dots.

As comedy sketch troupe Late Night Gimp Fight enliven the bill in the alternative tent with a song about bestiality (none of which is printable) and the cult acts take over the Festival Republic stage for the afternoon – Fidlar rattling out Ramones punk and No Sleep Til Brooklyn pastiches about cocaine; Savages merging Siouxsie and the Banshees with Lynchian atmospherics – we go in search of a hidden treasure. We find it on the BBC Introducing stage, calling itself Family of the Year. Californian alt-pop at its finest, they have a Lana Del Rey keyboardist, a knees-outta-his-jeans bassist and the exuberance of a west coast Grouplove. Singing leftfield folk party tunes about rocking in the afterlife, nights of "campfires and MDMA" in the shadow of the Joshua Tree, and the rude notes from neighbours they tear up at dawn, they're a vivacious and brilliant evolution of the Cali-folk cult. Think a Mumford & Sons you wouldn't want to kill, dismember and feed to coyotes. A diamond in the dirt.